Electric lamp



Sept. 5, 1939. M. E. MACKSOUD ELECTRIC LAMP Filed Dec. 8, 1936 2 Sheets-Sheet l "0-020 VOLT;

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IIO-IZOVOLT AC J DC Patented Sept. 5, 1939 i UNITED. STATES PATENT OFFICE amc'rarc mm Michel a. Mumua'st. Albans, N. Y., assignor to Macksoud Patents, Inc., New York, N. Y., a corporation of New York Application December 8, 193(i, Serial No. 114,789

15 Claims. (Cl. 1761.1)

This invention relates to electric lamps and, in one aspect, consists in a lamp containing in a unitary structure several 'light sources, each dependent upon the other for energization or control or both. In another aspect it consists in improvements in electric lamps of the type having a part of .the surface of the enclosing bulb fashioned into'a reflecting medium so that the light' of the lamp is directed and concentrated in a predetermined beam or field.

One of the objectsof the invention is to increase the efliciency of reflecting incandescent .lamps by combining with anincandescent filament other sources of illumination within the same bulb enclosure, hooded and directed by the I same reflecting surface, and energized directly or indirectly by the same current which heats the incandescent-filament. The other sources of iilumination may be are discharge of one type or another, or may comprise fluorescent bodies or surfaces properly placed 'within the bulb and which become luminous and emit light of certain definite color in the presence of the otherwise wasted ultraviolet rays from either the are. discharge or the incandescent filament.

Another object of this invention is to. make use of two or three different sources of illumination and difierent kinds of light, which may be of di'fierent and of predetermined colors, and 01' predetermined intensity, to produce a combined light that is closelyidentical in quality and spectrum range with daylight, or any other desired color or wave length range. For example, using a mercury arc and a tungsten-filament, the former being distinctly blue and the latter yellow and almost complementary to the blue of the mercury arc, the spectrum of the light generated by each source may be so proportioned that the resulting-combination will be close to daylight, or white light. Since the light generated-by a high intensity mercury arc is much more efllcient than the light from a tungsten filament, roughly 40 lumens per watt against 20 iumens-per watt,

it is desirable, from an eiflciency'standpoinhjo use as much of the blue light from the are as possible, and since this would tendto make the resulting combined light from the two sources too blue, as another important part of my invention, I contemplate correcting this too blue re sulting light by adding more yellow light from,

another source, as for example, byusing a fluorescent material which glows with a yellow light in the presence of the ultra-violet emitted by the mercury arc. Anthracene, eosine, escaiine, flu

orescein, naphalin, quinine sulphate, reeoreln blue and rhodamin are suitable fluorescent materials that will. act in this manner.

In general, an object of the invention is to produce a novel and greatly improved electric lamp for purposes of illumination, having a much higher lighting efliciency consistent with reasonable life than any other filament incandescent lamps now available on the market, and one which can be made to produce light having daylight characteristics as far as spectrum distriis'well understood that the smaller the light source, the nearer to a theoretical point source, the more accurately may thereflecting surface be shaped and proportioned to the light-source source-isof very great'importance. Moreover, it 4 and the more accurately will the light reflected by this surface be handled. Because of these considerations it is desirable to make the small bulb or tube containing the mercury or other are so of relatively small dimensions and to locate the filament as near to this small bulb or around its geometrical center as possible, so that the light may be considered as coming from the smallest possible source, thus bringing the total area or 35 volume 'of the light source into proper relation to the reflecting surface designed to cooperate with it. In any case it is obvious that the light source can not be considered as a point source, for it has actual and substantial dimensions.

-This makesreflector design more diiilcult, al-' though a fairly close approximation of the desired result is obtainable even with these relativelylarge light sources.

Thereflecting coating is useful on a bulb of such a lamp in that it actually cuts down the heat loss from the arc-bulb, that is, for given conditions of operatlomthe temperature of the arc-bulb is higher with the reflecting coating than without it. This is an important consideration with small high temperature and .thereiore high pressure arcs, as is well understood by those well versed in the art. The useot the arc-bulb enclosed within a second bulb in which 'a relativeiy high-vacuum is to ings sulatethe arc-bulb from the surrounding air,

the only 'connection between the arc-bulb and the outside enclosing bulb being the necessary leads and wire supports. A reflecting coating 5 hooding both the arc and the fllament is a novel and important feature of the invention, valuable because it not only directs the emitted light rays in a predetermined pattern, but which also reflects part of the rays of both light and heat so that they fall on the arc-bulb itself, and so tend to raise its temperature. This method of reducing heat losses to the outside air from the arc-bulb increases the efliciency of the novel lamp of my invention.

this case preferably on the inside of the bulb, has made it possible to further increase theefilciericy 'of this lampby employing a fluorescent material on chosen areas of the inside of the lamp, 0 which willglow in the presence of the ultraviolet light emitted in considerable amount by the arc source, and to a less extent by a high temperature incandescent filament. Since the ultraviolet light is emitted in all directions from 5 the surface of the arc-tube and of certain filaments that may be used in conjunction with such an are, it would be necessary to surround the combined light source completely. with the fluorescent material, if it. were desired to convert all Y of this ultra-violet light into visible light, Such an arrangement would not be desirable since these fluorescent materials do not transmit light readily, even when veryflnely divided, .and' are often entirely opaque. In a non-reflecting lamp in which. it was desired to employ such opaque and semi-opaque fluorescent materials, it is obvious that wherever such a substance is applied to the surface of the enclosing bulb, for example, a reduction in transmitting eflicie'ncy will result.

. 40 However, I have found that a light coating of flnely'divided fluorescent materials may. be applied over the inside of that part of the bulb that acts. as'a reflecting surface without diminishing to the least degree the efllciency of 'the transmitting part of the bulb since there is no coating placed thereon, and without greatly reducing the reflecting efficiency of the reflecting portion of the bulb, since most of these flnely divided materials are reasonably good reflectors, and some are very good reflectors. Thus the reflecting bulb not only serves to conserve and .direct the lightso that it isused more effectively, and to reduce the heat losses from both -arc-tube and filament so that higher efllciencies afe obtained, but it j also makes. possible theefiective use of opaque ":0 tained. I have found satisfactory a relatively.

. 75 smaller bulb, or supported in a circle just below and semi-opaque fluorescent materials on a large Part of the bulb surface for the conversion of the invisible ultra-violet rays into visible light, with an appreciable increase in efllciency for the 00 combined lighting sources. Such fluorescent materials may be placed on other parts of the inner surface of the lamp, or in some instances on its entire surface.

, As has been pointed out fluorescent material employed may-be chosen so that the colpriof the converted light obtained will in part correct the color of the light fromv the other source or sources, so that daylight or -some other desired spectrum range will be obsmall cylindrical bulb or tube containing proper leads, electrodes, starting gas and vaporizable iinetal, and mounted within a' larger reflecting bulb, wltha filament either supported around the The presence of the reflecting surface, and mshown in the accompanying drawings i which,

above, the particular the smaller bulb. If it is desired to make the distance between the electrodes relatively great and thereby increase the voltage drop between these electrodes and thus increase the percentage of the total energy from the circuit used .to 5 generate the blue light of the mercury are, for example, and of course at the same time reduce the percentage of energy used to heat'the somewhat shorter filament and so decrease the total amount of the yellowish light from this source, I have found it desirable to use a longer. cylindrical tube toenclose the arc. If a long tube for the arc placed in relatively the same position as the short arc-tube it is necessary to employ a longextemal reflecting bulb to enclose the whole, and although such an arrangement is possible and a satisfactory reflecting surface can be designed 'to handle the light from this long slender cylinder, I prefer when employing such a long arc-tube, to shapethe tube into a circle, 20 open of course for a short space where the electrodes are sealed in.

It is believed that heretofore no electric lamp has been available which included in'a unitary structure three sources'of light as herein shown which may be given complementary. characteristics in the production of 'a beam of selected light value as disclosed herein in accordance with the present invention. The utilization of ultra-violet light radiation from an incandescent fllament to activate a fluorescent or phosphorescent material is also believed to be novel, as is also an electric lamp having a fluorescent source. of light which is energized independent of external transformers and the like in a unitary lamp structure. I

- These and other features of the invention will be best understood and appreciated I from the description of two pre'fered embodiments there-- of, selected for purposes of illustrat'on and.

Fig. 1 15-11 View in elevation of a complete lamp, portions of the bulb being shown as broken away,

' Fig. 2 is a circuit diagram of the lamp,

Fig. 3 is a view in elevationof the arc-tube and filament as seen at right angles from their posi'-, tion in Fig. 1, f

Fig. 4 is a view in elevation of a complete. lamp having a different form of arc-tube from that shownin Fig. 1,

Fig. 5 is a circuit diagram of the lamp of Fig. 6 is,a fragmentary view on an enlarged scaleof the lowerend ofthe arc-tube,

Fig. 7 is a detailed view showing the manner in which the arc-tube is supported in the lamp.

The lampcfFig. lis shown ascomprising a bulb in of more or less conventional'shape provided internally with a coating of silver or other reflecting medium which extends contin uously from a line in the neck of the bulb substantially to its line of maximum diameter. The bulb is provided with a threaded metal base I! of usual construction and includes a hollow glass stem l4 having a flare l3 which is sealed to the bulb, At its inner end. the stem has a flattened press in which the lead and supporting wires are sealed, all as inxstand'ard incandescent lamp construction. The bulb may contain argon, ni-

trogen or other inert gas and may have fluorescent material 19, such as eosine,naphalin etc. distributed over all or a portion of its reflecting coating II. The arc-tube 20 has two upright legs 7o. pleted through the stem.

longer mercury arc.

insulated by mica llars 22. The rings 2| are preferably made in mesh form in order to interfere as little as possible with the emission-of light from the tube and the glass of the tube is protected from excessive heat from them by means of themica collars 22. Thering 2|, which'in Fig. 1 is located upon the left leg of the arc-tube, is connected by welding or otherwise to 'a supporting wire 23 which is sealed into the press of the stem l4. The'ring 2| shown in Fig. 1 as located upon the right leg of the arm-tube is similarly connected to alead wire 24 which is sealed into the press of the stem 14 and which is, connected at its outer end to the insulated center terminal .of the base l2. The ring 2|, encircling the midsection of the arc-tube, is connected to a dead supporting wire 25 sealed into the press of the A self-heating-electrode 26 is sealed into the upper end' of each leg of the arc-tube. In thepreferred embodiment of my invention I employ main electrodes having the form shown in-Figs. 1 and 3. A mandrel consisting of a straight length 'of wire with the arcing end wound into a few urns of a spiral from A to A in diameter is covered with a much finer wire wound in a spiral about the spiral part of the mandrel. The mandrel may be made of tungsten or other metal that will not melt at the operating temperature, and the finer wire wound on it may be of tungsten Containing a relatively high content of thorium, or this finewire may be of tungsten coated with barium or some similar metal. The purpose of this construction is to oifer as much surface of highly emissive material as possible,- and also to maintain a high ratio-of such surface to the mass of the material being heated, so that the starting-up period is-reduced to a minimum. The reater the mass of electrode to be heated the longer the delay between the first flash of the neon glow, and the final completion of the much Moreover, I have found it advisable to wind the fine wire on the spiral mandrel loosely, so that there is not a tight contact between the fine .wire and the mandrel with the result that heat flows from the fine wire slowly,

'thus allowing it to become heated before the mandrel is heated. If the contact between the wires were tight, then theywould both tend to be heated at the same rate, and the great capacity, relatively, of the mandrel would require a much longer time to arrive at starting temperature. To

accomplish this desired result, I prefer to wind the coil of the fine wire on a different straight mandrel of slightly larger diameter, and then slip the coil thus produced onto and around the few coarse spirals of the mandrel proper; For example, I have found that the coil wound on a mandrel of 0.026 inch diameter, will .flt properly and give the desired results, when it is slipped on the mandrel of the electrode when this mandrel is 0.20 inch in diameter. v

In-Ffig. 1 the right hand electrode 231s shown as connectedv tothe lead wire 28 which passes v throughthe press of the stem and is soldered to the threaded metal base l2. The electrode in the left leg of the arc-tube is connected by a wireJ'l, to the supporting wire 23 above mentioned, the circuit to this plectrode being com,--

filament' 3|; and-the lead 24 as ,Iwill be presently explained.

' A'st'artin'g electrode "is sealed into one side ,of thearc-tube at a point adjacent to the right hand main electrode 26;. The wire of the startl4 and is connected to the lower end of a resistance coil I which is wound upon a sleeve 11 of insulating material, such as lavite, and slipped ctelescopically upon the exhaust tube ll whichis sealedintothe stem I4 and passes out of the bulb through the stem in the usual manner. In accordance with a feature of the present invention this exhaust tube is utilized as a support or mandrel for the resistance coil l8.

The end of the starting electrode 2! within the arc tube 23 may be coated with a material of high emissivity such as barium. The arc bulb contains a small amount of mercury and a small amount of an inert gas such as helium, neon. argon, krypton, xenon, or combination of these or other inert gases. The amount of mercury and the pressure of the inert gas determines the resultant pressure of the mercury vapor and its spectrum.

FWhen current is turned on and during such interval before any are forms, there is a potential drop between the starting electrode 29 and the adjacent main electrode 23 of the full line voltage. The neon, or other inert gas ionizes practically at once between the electrodes 2! and 26, the amount of current carried being small and the voltage across this are being near the full potential ofthe line. As soon as the starting electrode 29 and some of the mercury in the arc tube .20

ing electrode is sealed into the press of the stem.

and its adjacent main electrode because the resistance of the longer path is much less than the resistance through the shorter gap and the high resistance of the coil II in series with the starting electrode. l A metallic reflecting disk l3 is located in the neck of the bulb in position to reflect rays which would otherwise be lost in the neck and thus to supplement the action of the reflecting coating ll of thebulb. The disk, ll is perforated for the passage of the lead and supporting wires and an insulating panel of mica' or the like is secured to the disk in registration with its perforation, for the purpose of insulating the lead and supporting wires from each other and'from the disk.

A filament 3|, which may comprise coiled tungsten wire, is supported beneath the circular portion of the ard -tube 20 inconcentric relation:

therewith by means of a series of glass projections 32 extending downwardly from the lower surface of the arc bulb and connected to the filament 3| through tungsten hooks 33. As"

already explained one end of the filament is connected tov the supporting wire 23'and the otherto the lead wire 24 above referred to. The lower lead'wire 24,,the filament 3|, the supporting wire 23 and the wire 21; the otherconnection comprising the lead wire 2... Due to the presence of ionized gas'at low pressure, the potential difference sets up a conductive path between the electrodes. The passage of current inthis mannertends to heat the electrodes, to vaporize the mercury and build up the mercury pressure within the tube. The presence of mercury vapor reduces the, resistance in the conductive'path and permits the arc to strike and build 'up in intensity. When this occurs the filament 3| vin series with the arc becomes incandescent due to the current flowing through it and its resistance effect becomes apparent so that the mercury vapor arc is limited in its current density by the resistance value of the incandescent fila- .ment. In other words the mercury vapor arc reaches .a maximum intensity corresponding to the current which the filament 3] will pass. Radiant energy generated by these sources, namely the filament 3| and the mercury arc, is

now received by the fluorescent material dis-" tributed upon the inner side of the reflecting coating .or on other portions ofthe bulb and this material consequently becomes a third light source within the bulb of the lamp. The action of the reflecting surface, besides deflningjhe concentrated beam or field 6: the lamp, is in part to reflect radiant energy back upon the arc-tube 2|! causing the mercury. vapor to operate under conditions of high and uniform temperature with resulting increase in intensity of light 30 supplied by the lamp. A further effect of the reflecting surface is to eliminate or reduce 2,171,:sao

' of the shorter piece uranium tubing. Finally the Pyrex or Corex glass of the arc tube itself is sealed to the hard uranium tube at near its central part. This seal has proved. satisfactory and climaticchanges which would otherwise effect the operation of the lamp. The temperature of the' arc-tube is therefore maintained more uniform 5 than would otherwise be the case, and the same is true as to its internal pressure and the character of its spectrum.

A second embodiment of my invention is illustrated in Figs. 4-7, the principal difference being 40 that in the latter modification a straight arctubeis employed instead of an arc-tube having a circular'body' portion of the character above described. Referring to Figs. 4-! it will be seen that the lampincludes a bulb 50 having a 'silvered reflecting coating 5| extending from a point in the neck of the bulb substantially to the line of maximum bulb diameter. The lamp includes a metal base 52 and a hollow stem 54 having a flare 53 which is sealed to the bulb. The'bulb tube 60 is supported below theend of the stem and is symmetrically placed in the main axis of the bulb. It is supported by a nickel mesh ring 6! insulatedfrom thetube by a collar 62 of mica or the like. The collar GI is connected by four supporting wires 63 to a ring 64 which is clamped upon the stem 54. A reflecting disk 5! of nickel or thelike, located between the end of the stem 54 and the arc-tube 60, is perforated for the passage of the lead and supporting wires and provided with an insulating panel for them. An electrode is sealed'in'to the lower end of the tube 60 and a similar electrode 66 is sealed into its upper end. These electrodes include a coiled mandrel upon which is loosely wound afinedoes not open in small cracks near the electrode, I,

due to the high temperatures employed as I have found an ordinary simple seal to do. i

The lead 6'! from the lower electrode 85 is connected to a dummy supporting wire 10 which is sealed into the press of the stem. The wire I0 is 10 connected to one end of a filament H which may be of coiled-tungsten wire and arranged in the form of a circle concentrically about the arc tube 60. The filament Ii is supp arted and held in shape by tungsten hooks sealed. into radially extending glass projections 12 on the outer walls of the arc tube. The other end of the filament H is connected through the lead wire 13 to the central insulated terminal of the lamp base.

The electrode 66, which is located inthe upper 6 end of the arc-tube, is connected by a lead wire 15 to the body of the base 52. Accordingly when the line voltage is impressed on the lamp'they two electrodes are,maintained at the full potential difference and when an arc discharge is established within the tube thefilament'IL. I

A starting electrode 11 is sealed into the upper end of the arc-tube 60 so that it extends'into a current flows through position adjacent to the up r main electrode 66. The starting electrode is connected through a wire 16 to the lower end of the resistance coil 56 already referred to and the resistance coil 56 is connected at its upper end through a wire H,

to the lead wire 13 and thus to the terminal of the base. h I The bulb 60 contains a small amount of; me-

tallic mercury and is filled with argon, krypton,

xenon 'or similar inert gases. Accordingly, whet 1..

the line voltage is impressed upon the lamp, a 40 glow. discharge is immediately established between the starting electrode and the main electrode 66. -The heating effect of this'discharge and of the radiant energy reflected by the coat- I ing 5| warms the arc-tube as above explained, so

that the mercury arc may strike, the filament Ii be-raised to incandescence, and the fluorescent material caused to glow. The light fromthese three sources -is blended, concentrated and diintending-to limit it to the details of construction the metal of theflectrodes may be accomplished, 1

79 as indicated in Fig. 6, by. first covering the wire I with a c16se-fltting tube I of clear 705 glass and sealing the ends of this sort glass tothe metalof the'electrode. A second and shorter tube 69 of hard uranium 'glass ,is next fitted over the rected by the reflecting coating of the lamp in a 50 manner which willbe understood from the fore going description.

Having thus disclosed myinvention and described two:- embodiments thereof, -butwithout shown,- I claim and desire to secure by'Letters Patent:"' h i r 1. An' electric lamp having, in combination, a bulb provided with a reflecting surface, containing a; filament and an arc tube with electrodes arranged in electric circuit with the filament, the tube being so located with respect to the reflectingsurface as to receive reflected rays from the filament.

bulb-provided with avcurved' reflecting surface, a filament mounted within-the bulb, and an arc tube located adjacent to the filament and to the focus of the reflecting surface, whereby light from defined beam and rays from both sources are renected-upon the-arc tube.

N 3. An electric lamp having, in combination, aj bulb provided witha curved reflecting surface,

An electric lamp having,'in combination, a

the filament and are tubeis concentrated in a an arc tube and a filament located withinthe 75.

bulb and hooded by said deflecting surface, the filament being mounted adjacent to the arc tube in position to heat the same, and the arc tube'being located in position to receive rays reflecte by the reflecting surface of the bulb.

4. An electric lamp having, in combination a bulb provided with a curved reflecting surface, a filament,- amercury vapor tube'mounted within the bulb hooded by the reflecting surface and 1 arranged to receive heat rays therefrom, heater coils insaid mercury vapor tube and a circuit-- connecting coils.

5. An electric lamp having a bulb with an internal reflecting surface thereon, fluorescent material distributed upon said reflecting surface, and an arc-tube and a filament mounted within the filament inseries with the heater the bulb in'position to emit radiation to said.

fluorescent material, the arc-tube being so located as to receive heat rays from said internal reflecting surface and .the combined light from allconcentric relation thereto, and serving as a source of radiation reflective by said surface to said body portion.

7. An electric lamp comprising a bulb having a reflecting surface thereon, an arc-tube having straight end portions and a circular portion located within the confines of the reflecting surface and symmetrically disposed with respect to the focus of the reflecting surface to receive radiation therefrom, said end portions being directed toward the neck of the bulb, a filament arranged concentrically with respect to the said surface and supported by the circular portion of the arctube, and serving as a source of radiation reflective by said surface to said circular portion.

, 8. An electric lamp for producing light of predetermined spectrum characteristics, comprising a'bulb enclosing a high pressure, high temperature arc-tube, a filament in circuit therewith and 50 fluorescent material dispersed over a part of the inner walls of the bulb, and a reflecting surface on the bulb shaped to hood said arc-tube and to blend, direct and concentrate the rays from all three sources in'a defined beam. 55 9. An electric lamp comprising a bulb having a reflecting surface upon a portion of its wall areas. an incandescent light source within the bulb, and

a relatively long arc-tube mounted within the bulb and having a circulanbody portion disposed m symmetrically to the focus of said reflecting surface and arranged to receive maximum uniform radiation, reflected-from said light source, by said surface, throughoutits entire length.

10. An electric lamb comprising a-gas filled outer bulb having reflecting wall areas, an incandescent light source within the bulb, an arctube of substantial length having a circular portion disposed with its-axis in a plane at right angles to the main axis of the bulb and within the confines of said reflecting areas whereby the temperature of the arc-tube is increased by rays from said light source, reflected by said areas.

11. An electric lamp comprising an outer bulb having a reflecting coating upon a part of its area, an arc-tube having substantially parallel legs and an intermediate tubular portion curved on -a circular axis and disposed concentrically within the coated part of the bulb, and a coiled filament supported adjacent to the arc-tube and Q substantially concentric with respect to its circularv portion whereby the arc-tube may receive direct radiation from the filament, the reflecting coating acting to direct the combined light rays of the arc-tube and filament outwardly in a defined beam.

v 12. An illuminating electric lamp comprising a gas filled bulb, means within said bulb including a filament and gas ionizing electrodes for producing visible and ultra-violet light, means forming a reflecting surface within said bulb for the reflection of visible light from said means out from said bulb, and fluorescent material distributed upon said surfaceand exposed to ultraviolet light from said first mentioned means for Producing additional visible light in said bulb for reflection by said surface from said bulb.

13. An illuminating electric lamp comprising a as filled bulb, means within said bulb for producing visible and ultra-violet light, means forming a reflecting surface within said bulb for the reflection of visible light from said means out from said bulb, and fluorescent material dis-' tributed upon said surface and exposed to ultraviolet light from said firstmentioned means for producing additional visible light in said bulb for reflection by said' surface from said bulb, said first mentioned means including thermionic and gas ionizing electrodes.

14. An electric illuminating lamp comprising a gas filled bulb, means forming a curved reflecting surface upon a portion of the interior surface of said bulb, a filament mounted adjacent the focus of said surface for producing light for re- A reduced by its, enclosure in the gas in said bulb,

said bulb for reflecting the light from said filament, and an arc-tube in said lamp substantially in the focus of said surface.

MICHEL E. MACKSOUD. 

